High material: quality fiber reinforced rubber, and flexible. Precise transmission: no slippage at work, with a constant gear ratio. Smooth transmission,: a buffer, damping capacity, low noise. High transmission efficiency, energy saving effect Specification Number of teeth: 20and60T Bore diameter: 5mm Timing belt length: 200mm Timing belt width: 6mm Color: Silver + black Material: Metal + rubber Package Contents: 8 * 2GT 5mm Bore Synchronous Wheel 8 * 2GT 5mm Bore Synchronous Wheel 60 Teeth 8 * Length 200mm width 6mm belt 4 x Hexagonal wrench Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.